Geometry+&+Material+export+Issues

=Issues Investigated and Observations=

Introduction
====//Though Revit and IES share the same gbxml file format, the export of model from Revit to IES is not 100% successful. Typically, the user needs to spend some time (depending on the complexity of model) to rectify any mistranslation of geometry/materials from Revit to IES. In a nutshell, for any project, the transfer of building information from Revit to IES is a matter of just mouse clicks.//==== ====//Typically, a mid-size project with a combination of variety of standard and non-standard geometric definition can require anywhere between a few hours to couple of days work to accurately redefine and rectify the inconsistencies in geometry transfer. Below are explained some of the commonly encountered issues.//====


 * A. Missing Surface Areas**

Seeing the ‘Check Rooms’ error message indicates missing surface areas. This is typical situation, which might occur due to incorrect room definitions, overlapping rooms, or gaps between rooms.

Even though each room can be isolated and viewed in the IES Toolkit Model Viewer, there is no way in to identify and isolate the part in the model that has the missing surface areas. Neither does Revit prompt any ‘error correction window,’ which could identify the section of model requiring attention. Thus, the user needs to have a thorough understanding of ‘room definitions‘ when defining rooms in the Revit model.

Missing areas in the model can cause errors in detailed thermal or CFD simulations. So it is recommended to have 0.00 ‘missing areas’. Though not advisable, missing areas of small magnitude (less than 2 sq.ft.) can be safely allowed in the model. However, in the case of larger missing areas, it is recommended to check the Revit model for room definitions.


 * B. Double Height volumes, rooms with different roof profiles / heights**

In the case of atriums with adjacent spaces overlooking into them, it is advisable to define the atrium space as a different room adjacent spaces as separate room. This can be done using ‘Room Separation’ from the Room and Area tab. When transferred to IES,VE constructs an internal partition between the Atrium volume and adjacent spaces.

Now, if the adjacent spaces are directly connected to the atrium space, i.e. there is no wall between the two, the user needs to define a hole in IES in the so-created ‘internal partition’. This can be done in two ways:
 * //By creating a hole// – In ModelIT, select the internal partition and from the ‘Add Hole’ button in the ModelIT button’s tab, select 100% from the drop down menu. This creates a hole in the internal partition and connects the two rooms as a single zone.
 * //By connecting spaces// – In the ModelIT, select the atrium space first, then click on the ‘Connect Spaces’ button in the ModelIT options tab. This pops up a new window. Select remove partitions in the ‘Connect Spaces’ window. With the window in background, select the adjacent room and click ‘Connect’ in the 'Connect Spaces' window. This connects the two spaces and removes any internal partitions.

Similarly, for spaces with a part of the area having a flat roof and the rest having light shafts / skylights, it is advisable to treat the flat roof area as separate while defining rooms and then add the hole to the internal partition in VE.

Materials and their thermal properties defined in Revit are transferred to VE. However, with the experimental model, color and texture definition were not seen to be transferred in VE. Color and texture are essential in understanding their impact in affecting light distribution in space.
 * C. Material attributes – Color and Texture**


 * Other common inconsistencies** in import of Building Information from Revit to IES:
 * 1) Floor to Ceiling height glazings contain wall surfaces on the top (window beam) and bottom (window sill)
 * 2) Horizontal glass canopies and skylights are imported as opaque surfaces and not as glass
 * 3) Sloped glazing elements are imported as wall elements and not as glass
 * 4) Double height spaces with adjacent overlooking spaces have internal partitions separating them – they are imported as separate room volumes instead of a single connected space

All of the above inconsistencies need to be rectified in IES ModelIT manually, and it is indeed time consuming for a fairly mid-sized model.

=Frequently asked Questions=

Some common issues observed (solutions yet to be identified) while working with IES:


 * 1) Identifying and rectifying missing surfaces is often a ‘Trial and Error’ process. Can users specifically know which portion is causing the error?
 * 2) How can I change materials from, say, concrete slab to glass for horizontal surfaces?
 * 3) Color and Texture of non-room bounding elements cannot be changed. Thus, renderings generated through Radiance look inconsistent with the actual appearance. How do I edit materials of ‘non-room bounding’ elements in VE?
 * 4) Radiance reports an error in generating simulation, and eventually the file cannot be used again. Any solutions?
 * 5) Can we assign materials attributes - color and texture - to individual wall / floor elements in Radiance, instead of assigning a generic color and texture?

Back to the Main Page Work Flow : Revit Architecture 2008 to IES 5.8.5